474 Life-histories of Northern Animals 



how it can harm them, Hving as they do in the water, where 

 it is not especially at home. Doubtless the only chance is 

 when the Beaver is ashore for material. The Fisher, the 

 Bear, the Wolf, and the Lynx are also to be reckoned with at 

 such a time, while the Otter is ever ready to satisfy its hunger 

 with Beaver meat if no fish are at hand. 



The Muskrat is considered, at least by the Beaver, to be 

 an enemy. It enters the Beaver pond as a sort of parasite 

 and works mischief there, as elsewhere, by piercing the dam 

 with its tunnel. The trappers generally maintain that a 

 Beaver recognizes the Muskrat as a mischief-maker and kills 

 it when the chance occurs. 



The coat of the Beaver seems to be infested with a trouble- 

 some parasite; the captive specimens in Zoos may often be 

 seen nibbling each other for a quarter of an hour at a time, 

 apparently to give and get the joy of scratching on places not 

 easily reached by the Beaver himself. 



In the plan of the Lost Creek or Yancey's Pond it will be 

 seen that many of the short pathways end at ant-hills; these 

 hills are the work of a small and wholly black ant that raises 

 its mound a foot or so above the marsh. The Beavers may 

 have sought these hillocks as lookout places, but there was 

 evidence of their staying a long time, and I wonder if they 

 did not go there for what is known in the west as a *'dry 

 wash"; that is, to let the ants pick off the parasites. Pos- 

 sibly, as noted already, the curious split or double nail on 

 the second toe of the hind-foot is an adaptation for combating 

 fur-lice. 



In this connection I may record an observation on the 

 Beaver's method of dealing with another minor pest. 



The patriarch and chief toiler in the big pond near 

 Yancey's, while attending strictly to business, was again and 

 again pursued by the Brewer blackbirds that nested in the 

 nearby swamp. They were very resentful birds, ready to 

 annoy any creature that came near their home ground. With- 

 out regard to law or order, again and again they united in a 

 noisy mob to tease the old Beaver as he calmly swam across 



